1. Field of the Invention
The present invention relates to a portable electronics device, and especially to a portable electronics device that comprises a chassis which has an interior space for storing a fuel vessel and a window formed thereto.
2. Description of the Related Art
In a portable electronics device represented by for example, a portable telephone, a laptop computer, a digital camera, a wrist watch, a PDA (Personal Digital Assistance), and an electronic organizer, etc., primary battery such as an alkaline battery and a manganese dry batter, or secondary battery such as a nickel cadmium battery, a nickel hydrogen battery, or a lithium-ion battery, are used as the power source. In recent years, as shown in Japanese Patent Application KOKAI Publication No. H9-147896, a fuel cell is used by electrochemically reacting liquid fuel such as methanol, etc., with oxygen, to directly obtain electric energy from the chemical energy.
The consumption of electric power of the electronic devices using primary and secondary batteries that are recently developed, is a large amount in accordance with the improvement of the performance of the device. Therefore, the driving time of the electronic devices is becoming shorter due to insufficient amount of battery. Further, in the case of a fuel cell, because the power source is liquid fuel, in order to solve the above problems, it is necessary to carry out supplement of liquid fuel or exchange to a new fuel vessel that has an enough amount of liquid fuel accumulated, before the operation of the electronics device is effected by shortage of liquid fuel.
To effectively exchange the fuel vessel, the remaining amount of fuel has to be consecutively confirmed.
However, if an electronic sensor, etc., is loaded to detect the remaining amount of fuel, various problems such as, the device main body becoming larger, the manufacturing cost rising, and the control of detecting the accurate remaining amount becoming difficult, leading to causes for malfunction, etc., occur.
The present invention has been made in consideration of the above, and an advantage of the present invention is that the remaining amount of liquid fuel in a fuel vessel can be confirmed by a simple structure, in a portable electronics device.